434 THE METHOD OF ORGANIC EVOLUTION. 



matter, wliicli constitute tbe very foundation of all life, and wliicli alone 

 render possible its countless manifestations in the animal and vegeta- 

 ble worlds; while those who have read Weissmann's account of the 

 complex processes of development of sperm and germ cells, in his vol- 

 ume on The (lerm Plasm, must feel sure that he, at all events, can have 

 no inadequate conception of their importance. 



What Darwinians deny is, as I understand the question, that these 

 laws themselves serve to keep the completed organism in close adapta- 

 tion to the fluctuating environment, instead of merely furnishing the 

 material wliich is required for that adaption. In our view, the funda- 

 mental laws of growth and development, through the agency of rapid 

 multiplication and constant variability, provide the material on which 

 ngiiural selection acts and by means of which it is enabled to keep up. 

 the adaption to the environment (which alone renders continuous life 

 and reproduction possible) during the constant though slow changes, 

 whether inorganic or organic, by which, in the course of ages, the 

 effective environment of each species becomes more or less profoundly 

 modified. Thus, and thus alone, we believe, are new species produced 

 in strict adaption to the new environment. So far as rendering possi- 

 ble and actually leading to growth, reproduction, and variation, the 

 fundamental laws are supreme. In securing the development of new 

 forms in adaption to the new environment, natural selection is supreme. 

 Hence arises the real distinction — though we may not always be able 

 to distinguish them — between specific and nonspecific or developmental 

 characters. Tbe former are those definite though slight modifications 

 through which each new species actually became adapted to its changed 

 environment. They are, therefore, in their very nature useful. The 

 latter are due to the laws which determine the growth and develop- 

 ment of the organism, and therefore they rarely coincide exactly with 

 the limits of a species. The more important of these latter characters 

 are common to much larger groups, as families, orders, or classes, while 

 others, depending partly on complex and fluctuating influences, are 

 variable even within the limits of a species. Of this kind are the finger 

 prints, which, like many other minute details of form or structure, vary 

 from individual to individual. 



I have now, I think, shown that the two most recent efforts to estab 

 lish new methods of organic evolution as either comijlete or partial 

 substitutes for natural selection — that is, for the survival of the fittest 

 among the individual variations annually produced — have completely 

 failed to establish themselves as having any relation to the actual facts 

 of nature. INIr. Bateson's discontinuous variations were long ago 

 rejected by Darwin as having no important part in the formation of 

 new species, while recent and ever-growing proofs of the generality 

 and the magnitude of individual variability render these larger and 

 rarer kinds of variation of even less importance than in his time. Mr. 

 Galton's theory of organic stability, which is essential to the success 



